From: Kent Overstreet <koverstreet@google.com>
To: linux-kernel@vger.kernel.org
Cc: Kent Overstreet <koverstreet@google.com>, axboe@kernel.dk
Subject: [PATCH 18/27] block: Add bio_copy_data()
Date: Tue, 19 Feb 2013 16:22:32 -0800 [thread overview]
Message-ID: <1361319761-23873-19-git-send-email-koverstreet@google.com> (raw)
In-Reply-To: <1361319761-23873-1-git-send-email-koverstreet@google.com>
This gets open coded quite a bit and it's tricky to get right, so make a
generic version and convert some existing users over to it instead.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
fs/bio.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/bio.h | 2 ++
2 files changed, 72 insertions(+)
diff --git a/fs/bio.c b/fs/bio.c
index 4ce24ee..e437f9aa 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -829,6 +829,76 @@ void bio_advance(struct bio *bio, unsigned bytes)
}
EXPORT_SYMBOL(bio_advance);
+/**
+ * bio_copy_data - copy contents of data buffers from one chain of bios to
+ * another
+ * @src: source bio list
+ * @dst: destination bio list
+ *
+ * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
+ * @src and @dst as linked lists of bios.
+ *
+ * Stops when it reaches the end of either @src or @dst - that is, copies
+ * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
+ */
+void bio_copy_data(struct bio *dst, struct bio *src)
+{
+ struct bio_vec *src_bv, *dst_bv;
+ unsigned src_offset, dst_offset, bytes;
+ void *src_p, *dst_p;
+
+ src_bv = bio_iovec(src);
+ dst_bv = bio_iovec(dst);
+
+ src_offset = src_bv->bv_offset;
+ dst_offset = dst_bv->bv_offset;
+
+ while (1) {
+ if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
+ src_bv++;
+ if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
+ src = src->bi_next;
+ if (!src)
+ break;
+
+ src_bv = bio_iovec(src);
+ }
+
+ src_offset = src_bv->bv_offset;
+ }
+
+ if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
+ dst_bv++;
+ if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
+ dst = dst->bi_next;
+ if (!dst)
+ break;
+
+ dst_bv = bio_iovec(dst);
+ }
+
+ dst_offset = dst_bv->bv_offset;
+ }
+
+ bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
+ src_bv->bv_offset + src_bv->bv_len - src_offset);
+
+ src_p = kmap_atomic(src_bv->bv_page);
+ dst_p = kmap_atomic(dst_bv->bv_page);
+
+ memcpy(dst_p + dst_bv->bv_offset,
+ src_p + src_bv->bv_offset,
+ bytes);
+
+ kunmap_atomic(dst_p);
+ kunmap_atomic(src_p);
+
+ src_offset += bytes;
+ dst_offset += bytes;
+ }
+}
+EXPORT_SYMBOL(bio_copy_data);
+
struct bio_map_data {
struct bio_vec *iovecs;
struct sg_iovec *sgvecs;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b20a9cd..90d36c6 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -286,6 +286,8 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
}
#endif
+extern void bio_copy_data(struct bio *dst, struct bio *src);
+
extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
unsigned long, unsigned int, int, gfp_t);
extern struct bio *bio_copy_user_iov(struct request_queue *,
--
1.7.12
next prev parent reply other threads:[~2013-02-20 0:26 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-20 0:22 [PATCH 00/27] Block cleanups - prep work for immutable bio vecs/dio rewrite Kent Overstreet
2013-02-20 0:22 ` [PATCH 01/27] block: Reorder struct bio_set Kent Overstreet
2013-02-20 0:22 ` [PATCH 02/27] block: Avoid deadlocks with bio allocation by stacking drivers Kent Overstreet
2013-02-20 0:22 ` [PATCH 03/27] block: Fix a buffer overrun in bio_integrity_split() Kent Overstreet
2013-02-20 0:22 ` [PATCH 04/27] block: Convert integrity to bvec_alloc_bs() Kent Overstreet
2013-05-09 19:43 ` Bjorn Helgaas
2013-02-20 0:22 ` [PATCH 05/27] block: Add bio_advance() Kent Overstreet
2013-02-20 0:22 ` [PATCH 06/27] block: Refactor blk_update_request() Kent Overstreet
2013-02-20 0:22 ` [PATCH 07/27] md: Convert md_trim_bio() to use bio_advance() Kent Overstreet
2013-02-20 0:22 ` [PATCH 08/27] block: Add bio_end_sector() Kent Overstreet
2013-02-20 0:22 ` [PATCH 09/27] block: Use bio_sectors() more consistently Kent Overstreet
2013-02-20 16:43 ` Ed Cashin
2013-02-20 0:22 ` [PATCH 10/27] block: Change bio_split() to respect the current value of bi_idx Kent Overstreet
2013-02-20 0:22 ` [PATCH 11/27] block: Remove bi_idx references Kent Overstreet
2013-02-20 0:22 ` [PATCH 12/27] block: Remove some unnecessary bi_vcnt usage Kent Overstreet
2013-02-20 0:22 ` [PATCH 13/27] block: Add submit_bio_wait(), remove from md Kent Overstreet
2013-02-20 0:22 ` [PATCH 14/27] raid10: Use bio_reset() Kent Overstreet
2013-02-20 0:22 ` [PATCH 15/27] raid1: use bio_reset() Kent Overstreet
2013-02-20 0:22 ` [PATCH 16/27] raid5: " Kent Overstreet
2013-02-20 0:22 ` [PATCH 17/27] raid1: Refactor narrow_write_error() to not use bi_idx Kent Overstreet
2013-02-20 0:22 ` Kent Overstreet [this message]
2013-02-20 0:22 ` [PATCH 19/27] pktcdvd: use bio_copy_data() Kent Overstreet
2013-02-20 0:22 ` [PATCH 20/27] pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage Kent Overstreet
2013-02-20 0:22 ` [PATCH 21/27] raid1: use bio_copy_data() Kent Overstreet
2013-02-20 0:22 ` [PATCH 22/27] bounce: Refactor __blk_queue_bounce to not use bi_io_vec Kent Overstreet
2013-02-20 0:22 ` [PATCH 23/27] block: Add bio_for_each_segment_all() Kent Overstreet
2013-02-20 0:22 ` [PATCH 24/27] block: Convert some code to bio_for_each_segment_all() Kent Overstreet
2013-02-20 0:22 ` [PATCH 25/27] block: Add bio_alloc_pages() Kent Overstreet
2013-02-20 0:22 ` [PATCH 26/27] block: Add an explicit bio flag for bios that own their bvec Kent Overstreet
2013-03-26 18:11 ` Andrew Morton
2013-03-26 19:42 ` Kent Overstreet
2013-02-20 0:22 ` [PATCH 27/27] bio-integrity: Add explicit field for owner of bip_buf Kent Overstreet
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